Fourth generation (4G) cellular networks employing newer radio access technology systems that implement the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) and LTE Advanced (LTE-A) standards are rapidly being developed and deployed within the United States and abroad. LTE-A brings with it the aggregation of multiple component carriers (CCs) to enable this wireless communications standard to meet the bandwidth requirements of multi-carrier systems that cumulatively achieve data rates not possible by predecessor LTE versions.
Within both LTE and LTE-A telecommunication networks, the mobility management entity (MME) and the enhanced NodeB (eNodeB) base station are independently responsible for implementing various control-plane signaling procedures. For example, the MME is responsible for establishing and releasing radio bearer connections for user equipment (UE), affecting UE transitions from idle mode to connected mode (and vice versa) by generating corresponding paging messages, implementing various communication security features, etc. This functionality is referred to as the Non-Access Stratum (NAS) within the LTE protocol architecture, which represents operations and communications between the evolved packet core (EPC) and the UE; the Access Stratum (AS) represents operations and communications between the eNodeB and the UE within the LTE protocol architecture.
The eNodeB is responsible for various radio resource control (RRC) control-plane activities, including system information broadcasting, transmitting paging messages emanating from MMEs, RRC parameter configuration for UEs, network cell selection and reselection procedures, measurement and reporting configuration for UEs, etc. In various implementations, RRC control plane signaling may be performed in conjunction with one or more of the following LTE protocol entities or layers: the packet data convergence protocol (PDCP), the radio link control (RLC) layer, the medium access control (MAC) layer, and the physical (PHY) layer. Further, both control-plane data and user-plane data can be multiplexed within the MAC layer and communicated to an intended recipient via the PHY layer, in the downlink (DL) or in the uplink (UL), during the same transmission time interval (TTI).
Regardless of which network device, e.g., an MME or an eNodeB in the DL, or a UE in the UL, is communicating LTE control-plane data, it is generally understood that control-plane data consists of time-sensitive information that must be communicated between or amongst various network devices in an efficient and predictable manner. Unfortunately, in modern LTE-A networks, which employ carrier aggregation to increase cumulative communications bandwidth and improve communications throughput, control-plane signaling (e.g., NAS or RRC communications) is not always designated to the most appropriate DL or UL communication resource, to ensure timely reception of sensitive control-plane data by one or more intended recipients. In fact, the present 3GPP LTE-A standard (i.e., relating to Releases 10-12) is silent with respect to identifying which network entity (e.g., a primary carrier cell or a secondary carrier cell) is designated to communicate control-plane data corresponding to one or more component carrier network cells during various DL communications.
As such, there exists a need for solutions that restrict control-plane data communications to pre-designated network entities or to dynamically-designated network entities as changing network conditions may require, particularly in view of various unanticipated radio link failure (RLF) scenarios. In this regard, it would be beneficial to improve the likelihood of communicating control-plane data in a timely manner within LTE-A networks employing carrier aggregation.